I examined electrical conduction in polymeric mu-cyclopentadienylelement (Cp-E) complexes of the main group elements using the nonequilibrium Green's function formalism with the density functional theory. The polymeric Cp-E complexes of group 1 elements, which had ionic Cp-E bonds, showed very low conductance. In contrast, the polymeric Cp-E complexes of groups 13 and 14 elements exhibited enhanced n-type electrical conduction when a bias was applied between the electrodes, because the delocalized electronic states of the lowest unoccupied molecular orbital were within the bias window.